Nokea
What is the meaning of the word 'enlist' as it is used in the second paragraph?
- A. call into service
- B. write down
- C. send away
- D. put across
Correct Answer: A
Rationale: In the context of the immune system, 'enlist' means to call into service. Immune cells recruit other cells to fight infection by producing chemicals that regulate their growth, behavior, and direct new recruits to trouble spots. This process is essential for the immune system's defense mechanism. The other choices are incorrect: 'write down' and 'put across' do not capture the action of mobilizing immune cells, and 'send away' is opposite in meaning to what is happening in the immune response.
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What is the meaning of the word 'pathogens' as it is used in the first paragraph?
- A. diseases
- B. vaccines
- C. disease-causing substances
- D. foods
Correct Answer: C
Rationale: In the context provided, 'pathogens' refers to disease-causing substances such as bacteria and viruses. These microorganisms can contaminate food and lead to foodborne illnesses. Choice A ('diseases') is incorrect as pathogens themselves cause diseases but are not diseases. Choice B ('vaccines') is incorrect as vaccines are used to prevent diseases caused by pathogens. Choice D ('foods') is incorrect as pathogens are not foods, but rather contaminants that can be found in food.
What is the meaning of the word 'sterile' as it is used in the second paragraph?
- A. free of bacteria
- B. healthy
- C. delicious
- D. impotent
Correct Answer: A
Rationale: In the context provided, 'sterile' means free of bacteria. The text mentions that raw foods are not sterile and can be a common source of foodborne illnesses due to contamination with harmful bacteria. 'Healthy' (choice B) is incorrect as the term 'sterile' specifically refers to the absence of bacteria, not overall health. 'Delicious' (choice C) is irrelevant to the context of bacteria contamination. 'Impotent' (choice D) is also incorrect as it does not relate to the concept of being free from bacteria.
What is the author's primary purpose in writing the essay?
- A. To persuade the reader to have an ECG
- B. To entertain the reader with a heartwarming story
- C. To inform the reader how an electrocardiograph reads the electric currents emitted by the heart
- D. To analyze the difference between the SA node and the AV node
Correct Answer: C
Rationale: The author's primary purpose in writing the essay is to inform the reader about how an electrocardiograph reads the electric currents emitted by the heart. Choice A is incorrect because there is no attempt to persuade the reader to have an ECG. Choice B is incorrect because the essay is focused on providing information rather than entertaining with a heartwarming story. Choice D is incorrect as the essay does not primarily analyze the difference between the SA node and the AV node; instead, it focuses on explaining how an electrocardiograph reads electric currents from the heart.
What is the meaning of the word 'ideal' as it is used in the first paragraph?
- A. thoughtful
- B. confined
- C. hostile
- D. perfect
Correct Answer: D
Rationale: In this context, 'ideal' means perfect. The human body provides a perfect environment for many microbes, as stated in the extract. It is the immune system's role to keep these microbes out or destroy them. The other choices are incorrect: 'thoughtful' does not fit the context of the sentence, 'confined' and 'hostile' are not synonymous with 'ideal' in this context.
What are the three steps of the 'wave of excitation'?
- A. The discharge from the SA node, the peak ECG, and the excitement of the ventricle.
- B. The excitement of the ventricle, the relaxing of the ventricle, and the systemic neural response.
- C. The contraction of the atrium, the relaxation of the atrium, and the contraction of the ventricle.
- D. The excitation of the atrium, the excitement of the ventricle, and the relaxing of the ventricle.
Correct Answer: D
Rationale: The correct steps of the 'wave of excitation' are the excitation of the atrium, excitement of the ventricle, and relaxation of the ventricle. In the described process, the 'wave of excitation' starts with the discharge from the SA node, leading to the excitation of the atrium. Next, the peak ECG corresponds to the excitement of the ventricle, not its relaxation. Finally, the wave concludes with the relaxation of the ventricle, not its contraction. Therefore, choices A, B, and C are incorrect as they do not accurately describe the sequential steps of the 'wave of excitation' as presented in the extract.